Process for preparing amines by conditioning the catalyst with ammonia

ABSTRACT

The invention relates to a process for preparing amines by conditioning the catalyst with ammonia.

The invention relates to a process for preparing amines by conditioningthe catalyst with ammonia.

The preparation of amines and diamines by means of catalytichydrogenation of the corresponding nitrites or by catalytic reductiveamination of the aldehydes or ketones is known. Suitable examples arenickel catalysts, copper catalysts, iron catalysts, palladium catalysts,rhodium catalysts, ruthenium catalysts and cobalt catalysts.

For many applications, cobalt catalysts and ruthenium catalysts arepreferred, since they have a high selectivity with respect to theformation of primary amines (cf., for example, Jiri Volf and JosefPasek, “Hydrogenation of Nitriles”, Studies in Surface Science andCatalysis, 27 (1986) 105-144; Silvia Gomez et al., “The ReductiveAmination of Aldehydes and Ketones and the Hydrogenation of Nitriles:Mechanistic Aspects and Selectivity Control, Adv. Synth. Catal. 344(2003) 1037-1057).

Numerous methods have been described for increasing the yield of primaryamine in nitrile hydrogenations or reductive aminations.

U.S. Pat. No. 6,521,564 (Roche Vitamins, Inc.) describes a process formodifying nickel and cobalt catalysts. Before their first use, thecatalysts are treated with a modifier. Examples of suitable modifiersare carbon monoxide, carbon dioxide, aldehydes and ketones. Thecatalysts are suspended in a solvent, treated with the modifier, removedfrom the solution, washed repeatedly and then used to hydrogenatenitrites. The catalysts thus modified have a higher selectivity withrespect to the formation of the primary amine than unmodified catalysts.A disadvantage of this process is the relatively complicatedmodification which necessitates additional process steps. In addition,there is the risk that the modifiers are partly released again duringthe hydrogenation process and hence adversely affect the product purity.

The modification with alkali metal hydroxides (U.S. Pat. No. 4,375,003),especially lithium hydroxide (EP 0 913 388), likewise leads to animprovement in the yield of primary amine. The catalysts can either betreated with alkali metal hydroxides before the reaction, or else thealkali metal hydroxide is added to the reaction mixture during thereaction. Provided that no relatively large amounts of solvents such asammonia, THF or methanol are used, the long-term stability of theLiOH-modified catalysts is quite good. In in-house experiments, however,we found that, when abovementioned solvents are used, the LiOH is washedcontinuously from the catalyst and the proportion of secondary aminesthus raises again. In a continuous process in which the solvent isremoved from the mixture by distillation and recycled into the process,there is additionally deposition of the alkali metal hydroxides in thedistillation columns. The columns have to be shut down at regularintervals and cleaned, so that the alkali modification leads indirectlyto production shutdowns.

According to EP 0 913 387, quaternary ammonium bases can also be used toincrease the selectivity. Especially in the case of use of a solvent,correspondingly modified catalysts have a significantly higher lifetimethan alkali-modified catalysts. A crucial disadvantage is the relativelyhigh cost of quaternary ammonium bases.

It has been stated many times that the addition of ammonia to thereaction mixture or the use of ammonia as a solvent in nitrilehydrogenations leads to an increase in the yield of primary amine. Thesame applies to reductive aminations, in which an excess of ammonia orthe use of ammonia as a solvent likewise has a positive effect on theyield (for example EP 449 089, EP 659 734, DE 12 29 078).

The positive influence of ammonia on the selectivity is frequentlyexplained by the following reaction scheme (see, for example, thereviews by: Jiri Volf and Josef Pasek, “Hydrogenation of Nitriles”,Studies in Surface Science and Catalysis, 27 (1986) 105-144; SilviaGomez et al., “The Reductive Amination of Aldehydes and Ketones and theHydrogenation of Nitriles: Mechanistic Aspects and Selectivity Control,Adv. Synth. Catal. 344 (2003) 1037-1057):

In the nitrile hydrogenation, according to (1), a hydrogen molecule isfirst added on to form an intermediate imine. For the imine, which alsooccurs as an intermediate in the reductive amination, there are severalpossible reactions. The addition of a further molecule of hydrogenaccording to (1) leads to the desired product, the primary amine.However, according to (2), an already formed primary amine can also addon to the imine, which leads to the formation of the undesired secondaryamine in the subsequent reaction steps. This secondary amine can in turnreact by addition onto an imine and subsequent elimination/hydrogenationto give the tertiary amine (not shown). The addition of ammonia to thereaction mixture leads to an increase in selectivity because ammonia isadded on to the imine according to (3) and thus suppresses the reactionof the imine with other amines. The subsequent hydrogenation of thegem-diamine leads to the target product, the primary amine. Onedisadvantage of the addition of ammonia to the reaction mixture is thereduction in the catalyst activity (see, for example, U.S. Pat. No.4,375,003 Example IX; C.D. Frohning in: J. Falbe and U. Hasserodt (Eds.)“Katalysatoren, Tenside und Mineralöladditive” [Catalysts, Surfactantsand Mineral Oil Additives], Georg Thieme verlag Stuttgart, 1978, p. 44ff.; Jiri Volf and Josef Pasek, “Hydrogenation of Nitriles”, Studies inSurface Science and Catalysis, 27 (1986) 105-144).

It has now been found that, surprisingly, the selectivity increase whichis achieved by the addition of ammonia to the reaction mixture can beenhanced significantly when the catalyst is additionally treated withammonia (conditioning) before it is used in the hydrogenation and onlythen is contacted with the reaction mixture composed of hydrogen,starting compounds and ammonia. The conditioning of the catalyst withammonia also has the advantage that the catalyst has a significantlyhigher activity than without conditioning.

The invention provides a process for preparing amines, diamines orpolyamines by means of catalytic hydrogenation and/or by catalyticreductive amination of the corresponding starting compounds in thepresence of ammonia, hydrogen and of at least one catalyst andoptionally of a solvent or solvent mixture, wherein the catalyst istreated (conditioned) with ammonia before the start of the hydrogenationor reductive amination.

The treatment (conditioning) of the catalyst can be carried out withgaseous, liquid or supercritical ammonia. When a solvent is used, theconditioning can also be effected with a mixture of the solvent(s) withammonia. In a preferred embodiment, the conditioning is effectedexclusively using liquid ammonia.

The conditioning can be carried out either at the pressure which arisesfrom the vapour pressure of the ammonia at the appropriate conditioningtemperature, or at elevated pressure of from 50 to 300 bar, preferablyfrom 200 to 250 bar, is employed. The pressure increase can quitegenerally be achieved by gases such as nitrogen, argon, and/or hydrogen.The only upper limit on the maximum employable pressure is the pressureresistance of the apparatus used. In a preferred embodiment, theconditioning with ammonia is effected additionally in the presence ofhydrogen. The partial pressure of the hydrogen used in the reactor is inthe range from 0.1 to 300 bar, preferably from 50 to 250 bar, morepreferably from 100 to 200 bar. Higher pressures than those specifiedabove have no adverse effects.

The conditioning can be carried out within a wide temperature range.Typically, temperatures between 20 and 180° C., preferably from 50 to130° C., are employed. Particular preference is given to passing througha temperature ramp in which the catalyst, beginning at moderatelyelevated temperature, preferably between 20 and 50° C., is heated slowlyto the reaction temperature desired later for the hydrogenation,preferably from 50 to 130° C.

In reactors which have only a low pressure resistance, it may, though,be advantageous to work at temperatures below room temperature in orderto lower the vapour pressure of the ammonia correspondingly.

The conditioning can in principle be effected actually before thecatalyst is introduced into the reactor. Especially in the case of fixedbed catalysts, it is, though, advantageous when the treatment of thecatalyst is effected with ammonia only after the catalyst has beenintroduced into the reactor. One means of this is to flood the fixed bedreactors with ammonia after the catalyst has been introduced, so thatthe entire amount of catalyst comes into contact with ammonia. However,preference is given to continuous treatment with ammonia in which aconstant ammonia stream through the reactor is preferably established.The amount of ammonia in this context is between 0.2 and 3 m³,preferably 0.5 and 2 m³ of ammonia per m³ of catalyst and hour. Tominimize the ammonia consumption, ammonia arriving at the reactor outletcan be recycled back to the reactor inlet either directly or afterpreceding purification, preferably distillation. The duration of theconditioning is dependent upon the amount of ammonia used and ispreferably between 1 and 48 hours, more preferably between 12 and 24hours. Longer periods do not adversely affect the result and arelikewise possible in the context of the invention. It is preferred thatthe conditioning is continued at least until the entire catalyst hasbeen saturated with ammonia, i.e., for example, in the case of a porouscatalyst, virtually the entire pore volume should be filled withammonia.

The catalysts used may in principle be all catalysts which catalyse thehydrogenation of nitrile and/or imine groups with hydrogen. Particularlysuitable catalysts are nickel catalysts, copper catalysts, ironcatalysts, palladium catalysts, rhodium catalysts, ruthenium catalystsand cobalt catalysts, very particularly cobalt catalysts. To increasethe activity, selectivity and/or lifetime, the catalysts mayadditionally comprise dopant metals or other modifiers. Typical dopantmetals are, for example, Mo, Fe, Ag, Cr, Ni, V, Ga, In, Bi, Ti, Zr andMn, and also the rare earths. Typical modifiers are, for example, thosewith which the acid-based properties of the catalysts can be influenced,for example alkali metals and alkaline earth metals or compoundsthereof, preferably Mg and Ca compounds, and also phosphoric acid orsulphuric acid and compounds thereof.

The catalysts may be used in the form of powders or shaped bodies, forexample extrudates or compressed powders. It is possible to useunsupported catalysts, Raney-type catalysts or supported catalysts.Preference is given to Raney-type and supported catalysts. Suitablesupport materials are, for example, kieselguhr, silicon dioxide,aluminium oxide, alumosilicates, titanium dioxide, zirconium dioxide,aluminium-silicon mixed oxides, magnesium oxide and activated carbon.The active metal may be applied to the support material in the mannerknown to the person skilled in the art, for example by impregnation,spraying or precipitation. Depending on the type of catalystpreparation, further preparation steps known to those skilled in the artare necessary, for example drying, calcining, shaping and activation.For the shaping, further assistants, for example graphite or magnesiumstearate, may optionally be added.

Preference is given to using catalysts as obtainable according to theteachings of EP 1 207 149 (catalysts based on an activated,alpha-Al₂O₃-containing Raney catalyst having macropores and based on analloy of aluminium and at least one transition metal selected from thegroup consisting of iron, cobalt and nickel and optionally one or morefurther transition metals selected from the group consisting oftitanium, zirconium, chromium and manganese), EP 1 207 149, EP 1 209146, U.S. Pat. No. 3,558,709, EP 880 996, EP 623 585, EP 771 784, EP 814098 (a catalyst which comprises, as the active metal, ruthenium alone ortogether with at least one metal of transition group I, VII or VIII ofthe Periodic Table applied to a support in an amount of from 0.01 to 30%by weight based on the total weight of the catalyst, from 10 to 50% byweight of the pore volume of the support being formed by macroporeshaving a pore diameter in the range from 50 nm to 10 000 nm and from 50to 90% of the pore volume of the support being formed by mesoporeshaving a pore diameter in the range of from 2 to 50 nm, the sum of thepore volumes adding up to 100%), EP 636 409 (cobalt catalysts whosecatalytically active composition comprises from 55 to 98% by weight ofcobalt, from 0.2 to 15% by weight of phosphorus, from 0.2 to 15% byweight of manganese and from 0.2 to 15% by weight of alkali metal,calculated as oxide, characterized in that the catalyst mass is calcinedin a first step at end temperatures of from 550 to 750° C. and in asecond step at end temperatures of from 800 to 1000° C.), EP 1 221 437,WO 97/10202 and EP 813 906 (a catalyst which comprises, as the activemetal, ruthenium alone or together with at least one metal of transitiongroup I, VII or VIII of the Periodic Table, applied to a support, thesupport having a mean pore diameter of at least 50 nm and a BET surfacearea of at most 30 m²/g, and the amount of the active metal being from0.01 to 30% by weight, based on the total weight of the catalyst, theratio of the surface areas of the active metal and of the catalyst being<0.05).

Particular preference is given to shaped catalysts as obtainableaccording to EP 1 216 985 (shaped hydrogenation catalyst based on Raneycobalt is used, which is characterized in that the Raney catalyst ispresent in the form of hollow bodies). Particular preference is likewisegiven to supported cobalt catalysts as described in EP 1 306 365, inwhich the crystals of the cobalt and of any nickel present have a meanparticle size of from 3 to 30 nm.

The process according to the invention is found to be advantageous inthe conversion of nitrites and the reductive aminations of ketones andaldehydes as starting compounds, since the yield of primary amine issignificantly increased by the treatment of the catalyst with ammonia.The corresponding starting compounds which are suitable for the processwill now be described. Suitable starting compounds are mono-, di- andpolynitriles, iminonitriles and aminonitriles. It is also possible toconvert compounds which contain one or more nitrile, imine and/or aminegroups and simultaneously one or more aldehyde and/or keto groups. It isalso possible to convert mono-, di- or polyaldehydes or mono-, di- orpolyketones and compounds which contain one or more aldehyde groups andsimultaneously one or more keto groups.

Furthermore, the process according to the invention is also suited forthe conversion of polyetherpolyols with ammonia to the correspondingpolyetheramines.

Preference is given to using cyclic compounds of the general formula (I)

-   A=CN, CH₃;-   e=0, 1;-   B=C═O, CH₂, CHR, CR₂, NH, NR, O;-   R=simultaneously or each independently, hydrogen, branched or    unbranched aryl, alkyl, alkenyl, alkynyl and cycloalkyl radicals,    which may be substituted or unsubstituted, and N-, O-, S- or    P-containing substituents which are bonded directly to the ring via    a heteroatom or carbon atom, and where no, one or two double bonds    may be present.

Examples of such compounds are:

Isophoronenitrile(IPN)

Oxoisophorone

3,5,5-Trimethylcyclohexanone(TMC-one)

2,2,6,6-Tetramethyl-4-piperidone

Isophorone

3,5,5-Trimethylcyclo-hexane-1,4-dione

Likewise suitable is 1,3- and 1,4-cyclohexanedialdehyde and mixturesthereof, of the formula

Particular preference is given to isophoronenitrile and3,5,5-trimethylcyclohexane-1,4-dione.

Preferred aromatic compounds are those of the general formula (II)

where the symbols are each defined as follows:

-   X: cyanide (CN), aldehyde (CHO) or keto group (CR¹O);-   R¹: simultaneously or each independently, hydrogen, branched or    unbranched aryl, alkyl, alkenyl, alkynyl and cycloalkyl radicals,    which may be substituted or unsubstituted, and N-, O-, S- or    P-containing substituents which are bonded directly to the aromatic    ring via a heteroatom or carbon atom;-   f: values from 0 to 5.

Preferred examples thereof are:

Benzaldehyde

Phthalonitrile,terephthalonitrile,isophthalonitrileand mixtures thereof

3,4-Dimethoxy-phenylacetonitrile

Preferred linear or branched compounds are those of the formula (III)

where the symbols are each defined as follows:

-   n: integers from 0 to 18;-   Y, Z: simultaneously or each independently, cyanide (CN), aldehyde    (CH), ketone (CR²⁰), hydrogen, CH₃, CR═CR² or amines (CNR₂ ²),-   R²: simultaneously or each independently, hydrogen, branched or    unbranched aryl, alkyl, alkenyl alkynyl and cycloalkyl radicals,    which may be substituted or unsubstituted, and N—, O—, S— or P—    containing substituents.

Preferred examples thereof are:

2,4,4- and 2,2,4-Trimethyladiponitrileand mixtures thereof

Adiponitrile

Fatty nitriles (alone or in mixtures)

1,6-Hexanedial

1,4-Butanedial

1,4-Butanedinitrile

Acrolein

3-Methylaminopropanenitrile

3-Dimethylaminopropanenitrile

3-Cyclohexylaminopropanenitrile

1-Diethylaminopentan-4-one

For the conversion of polyetherpolyols with ammonia to the correspondingpolyetheramines, polyetherpolyols with molecular weights between 200 and5000 g/mol are suited. Preferred examples thereof are:

Polyoxypropylenediols, with x=2-70

Poly(oxyethylen-oxypropylene)diols, a+c=2-6; b=2-40

In the process according to the invention, very particular preference isgiven to using isophorone-nitrile, trimethyladiponitrile, adiponitrile,isophoroneiminonitrile and isophoroneaminonitrile.

The invention is illustrated in detail by the examples which follow.

EXAMPLES Example 1 Aminating hydrogenation of3-cyano-3,5,5-trimethyl-cyclohexanone (isophoronenitrile) to3-amino-methyl-3,5,5-trimethylcyclohexylamine (isophorone-diamine) witha supported cobalt catalyst

The experimental apparatus consisted of a 100 ml fixed bed reactorcharged with ion exchanger according to EP 042 119 for catalysing theimine formation from IPN and ammonia, and a downstream fixed bed reactorcharged with 300 ml of a tabletted cobalt catalyst (kieselguhr support).To condition the catalyst, 300 ml/h (180 g/h) of ammonia were passedover the fixed bed at temperatures between 60 and 100° C. During theconditioning, a partial hydrogen pressure of approx. 100 bar wasestablished. After two hours, the conditioning had ended. Directly afterthe conditioning, 30 ml/h (approx. 28 g/h) of IPN and 400 ml/h (370 g/h)of ammonia were fed in. The two reactant streams were mixed immediatelyupstream of the reactor charged with ion exchanger. The result of thegas chromatography analysis of the product is listed in Table 1 below inthe “with conditioning” column.

Comparative Example A

The experiment was carried out with the same amount of fresh catalyst,but this time without ammonia conditioning (see Table 1, “withoutconditioning” column).

TABLE 1 Without With conditioning conditioning Comparative Analysisresult (GC %) Example 1 Example A Total isophoronediamine 88.4 83.7Total isophoroneaminonitrile 1.5 6.2 Imine (2-aza-4,6,6-trimethyl- 5.35.7 bicyclo[3.2.1]octane) Amidine (3,3,5-trimethyl- 0.7 2.36-amino-7-aza- bicyclo[3.2.1]octane) Others 4.1 2.1

With conditioning, the diamine yield is significantly higher thanwithout conditioning. This is attributable firstly to the higherconversion (less isophorone-aminonitrile intermediate in the product)and secondly to the higher selectivity (lower proportion of the cyclicamidine and imine by-products).

Example 2 Aminating hydrogenation of3-cyano-3,5,5-trimethylcyclohexanone (isophoronenitrile) to3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophoronediamine) with aRaney-type cobalt catalyst

The experimental apparatus consisted of a 100 ml fixed bed reactorcharged with ion exchanger according to EP 042 119 to catalyse the imineformation from IPN and ammonia, and a downstream fixed bed reactorcharged with 66 ml of a spherical Raney-type cobalt catalyst. Tocondition the catalyst, 100 ml/h (60 g/h) of ammonia were passed overthe fixed bed at approx. 100° C. During the conditioning, a partialhydrogen pressure of approx. 100 bar was established. After two hours,the conditioning had ended. Directly after the conditioning, 100 ml/h ofa 14% solution of IPN in ammonia were fed in (LHSV=1.5 h⁻¹). The resultof the gas chromatography analysis of the product is listed in Table 2below in the “with conditioning” column.

Comparative Example B

The experiment was carried out with the same amount of fresh catalyst,but this time without the ammonia conditioning (see Table 2, “withoutconditioning” column).

TABLE 2 Without With conditioning conditioning Comparative Analysisresult (GC %) Example 2 Example B Total isophoronediamine 94 91 Totalisophoroneaminonitrile 0.2 2.6 Imine (2-aza-4,6,6-trimethyl- 2.3 1.6bicyclo[3.2.1]octane) Amidine (3,3,5-trimethyl- 2 3.2 6-amino-7-aza-bicyclo[3.2.1]octane) Others 1.5 1.5

With conditioning, the diamine yield is 3% higher than withoutconditioning. This is attributable firstly to the higher conversion(less isophoroneaminonitrile intermediate in the product) and secondlyto the higher selectivity (lower proportion of the cyclic amidine andimine by-products).

Example 3 Hydrogenation of Trimethylhexamethylenedinitrile toTrimethylhexamethylenediamine

The experiments were carried out in a 1 l hydrogenation autoclave whichwas equipped with a catalyst basket (static basket with stirrer, Mahoneytype). The catalyst basket was in each case charged freshly with 80 mlof a spherical Raney-type fixed bed cobalt catalyst.

For conditioning with ammonia, the reactor was first charged withapprox. 500 ml of ammonia and kept at 50° C. and 250 bar with stirringfor approx. 2 h. The ammonia was then discharged by decompressing thereactor.

After the conditioning, 600 ml of a 20% solution oftrimethylhexamethylenedinitrile (mixture of the 2,4,4- and2,2,4-isomers) were hydrogenated at 120° C. and total pressure 250 barfor 6 h. The product was discharged and subsequently analysed by gaschromatography. The result is listed in Table 3 in the “withconditioning” column.

Comparative Example C

In the same way, an experiment was carried out in which the catalyst hadnot been conditioned beforehand with ammonia. The result is listed inTable 3 in the “without conditioning” column.

TABLE 3 Without With conditioning conditioning Comparative Analysisresult (GC %) Example 3 Example C Total trimethylhexamethylene- 90 84diamine Imine 4.8 6.2 Saturated cyclic compounds 1.8 2.6 Hydrogenatableintermediates 0.1 0.11 Further by-products 3.3 7

The conditioning of the catalyst with ammonia leads to a reduction inby-product formation with unchanged activity.

1. A process for preparing amines, diamines or polyamines by means ofcatalytic hydrogenation and/or by catalytic reductive amination of thecorresponding starting compounds in the presence of ammonia, hydrogenand of at least one catalyst and optionally of a solvent or solventmixture, characterized in that the catalyst is treated (conditioned)with ammonia before the start of the hydrogenation or reductiveamination.
 2. A process according to claim 1, characterized in that thetreatment (conditioning) of the catalyst is carried out with gaseous,liquid and/or supercritical ammonia.
 3. A process according to claim 1,characterized in that at least one solvent is used.
 4. A processaccording to claim 1, characterized in that the conditioning is effectedusing liquid ammonia.
 5. A process according to claim 1, characterizedin that the conditioning is carried out at the pressure which arisesfrom the vapour pressure of the ammonia at the appropriate conditioningtemperature.
 6. A process according to claim 1, characterized in thatoperation is effected at elevated pressure of from 50 to 300 bar.
 7. Aprocess according to claim 1, characterized in that the conditioning isadditionally effected by increasing the pressure by means of gases,preferably nitrogen, argon and/or hydrogen.
 8. A process according toclaim 7, characterized in that the partial pressure of the hydrogen inthe reactor is in the range from 0.1 to 300 bar.
 9. A process accordingto claims claim 1, characterized in that temperatures between 20 and180° C. are employed.
 10. A process according to claim 1, characterizedin that a temperature ramp is passed through, in which the catalyst,beginning at moderately elevated temperature, is heated slowly to thereaction temperature desired later for the hydrogenation.
 11. A processaccording to claim 1, characterized in that the conditioning is effectedbefore the catalyst is introduced into the reactor.
 12. A processaccording to claim 1, characterized in that the catalyst is conditionedwith ammonia after the catalyst has been introduced into the reactor.13. A process according to claim 1, characterized in that the catalystis conditioned by means of a continuous ammonia stream.
 14. A processaccording to claim 1, characterized in that the conditioning is effectedfor between 1 and 48 hours.
 15. A process according to claim 1,characterized in that the conditioning is continued until the entireamount of catalyst has been saturated with ammonia.
 16. A processaccording to claim 1, characterized in that nickel catalysts, coppercatalysts, iron catalysts, palladium catalysts, rhodium catalysts,ruthenium catalysts and cobalt catalysts are used.
 17. A processaccording to claim 1, characterized in that dopant metals are present inthe catalysts.
 18. A process according to claim 1, characterized in thatunsupported catalysts, Raney-type catalysts or supported catalysts areused.
 19. A process according to claim 18, characterized in that thesupport material used is kieselguhr, silicon dioxide, aluminium oxide,alumosilicates, titanium dioxide, zirconium dioxide, aluminium-siliconmixed oxides, magnesium oxide and activated carbon.
 20. A processaccording to claim 1, characterized in that fixed bed catalysts areused.
 21. A process according to claim 20, characterized in that thefixed bed reactors, after the catalyst has been introduced, are floodedwith ammonia, such that the entire amount of catalyst comes into contactwith ammonia.
 22. A process according to claim 1, characterized in thatthe starting compounds used are mono-, di- and polynitriles,iminonitriles or aminonitriles.
 23. A process according to claim 1,characterized in that the starting compounds used are mono-, di- orpolyaldehydes or mono-, di- or polyketones.
 24. A process according toclaim 1, characterized in that the starting compounds used are compoundswhich contain one or more nitrile, imine and/or amine groups andsimultaneously one or more aldehyde and/or keto groups.
 25. A processaccording to claim 1, characterized in that the starting compounds usedare compounds which contain one or more aldehyde groups andsimultaneously one or more keto groups.
 26. A process according to claim1, characterized in that the starting compounds used areisophoronenitrile (IPN), 3,5,5-trimethylcyclohexanone (TMC-one),isophorone, 3,5,5-trimethylcyclohexane-1,4-dione, oxoisophorone,2,2,6,6-tetramethyl-4-piperidone and 1,3- and 1,4-cylohexanedialdehyde,and mixtures thereof.
 27. A process according to claim 1, characterizedin that the starting compounds used are benzaldehyde, 3,4dimethoxyphenylacetonitrile and phthalonitrile, terephthalonitrile,isophthalonitrile and mixtures thereof.
 28. A process according to claim1, characterized in that the starting compounds used are 2,4,4- and2,2,4-trimethyladiponitrile and mixtures thereof, adiponitrile,1,6-hexanedial, 1,4-butanedial, 1,4-butanedinitrile,3-methylaminopropanenitrile, 3-dimethylaminopropanenitrile,3-cyclohexylaminopropanenitrile, 1-diethylaminopentan-4-one andacrolein.
 29. A process according to claim 1, characterized in thatisophoronenitrile, trimethyladiponitrile, adiponitrile,isophoroneiminonitrile and isophoroneaminonitrile are used.
 30. Aprocess according to claim 1, characterized in that polyetherpolyols areused.
 31. A process according to claim 1, characterized in thatcatalysts in which the crystals of the cobalt and of any nickel presenthave a mean particle size of from 3 to 30 nm are used.
 32. A processaccording to claim 1, characterized in that a catalyst which comprises,as the active metal, ruthenium alone or together with at least one metalof transition group I, VII or VIII of the Periodic Table applied to asupport in an amount of from 0.01 to 30% by weight based on the totalweight of the catalyst, from 10 to 50% by weight of the pore volume ofthe support being formed by macropores having a pore diameter in therange from 50 nm to 10 000 nm and from 50 to 90% of the pore volume ofthe support being formed by mesopores having a pore diameter in therange from 2 to 50 nm, the sum of the pore volumes adding up to 100%, isused.
 33. A process according to claim 1, in the presence of a catalystwhich comprises, as the active metal, ruthenium alone or together withat least one metal of transition group I, VII or VIII of the PeriodicTable, applied to a support, the support having a mean pore diameter ofat least 50 nm and a BET surface area of at most 30 m2/g, and the amountof the active metal being from 0.01 to 30% by weight, based on the totalweight of the catalyst, the ratio of the surface areas of the activemetal and of the catalyst support being <0.05.
 34. A process accordingto claim 1, characterized in that a shaped hydrogenation catalyst basedon Raney cobalt is used, which is characterized in that the Raneycatalyst is present in the form of hollow bodies.
 35. A processaccording to claim 1, characterized in that cobalt catalysts are usedwhose catalytically active composition comprises from 55 to 98% byweight of cobalt, from 0.2 to 15% by weight of phosphorus, from 0.2 to15% by weight of manganese and from 0.2 to 15% by weight of alkalimetal, calculated as oxide, characterized in that the catalyst mass iscalcined in a first step at end temperatures of from 550 to 750° C. andin a second step at end temperatures of from 800 to 1000° C.
 36. Acatalyst according to claim 1, characterized in that catalysts are usedwhich are based on an activated, alpha-Al2O3-containing Raney catalysthaving macropores and based on an alloy of aluminium and at least onetransition metal selected from the group consisting of iron, cobalt andnickel and optionally one or more further transition metals selectedfrom the group consisting of titanium, zirconium, chromium andmanganese.